Andrew Luck kept San Francisco's prime-time loss at Seattle in the background once his workday ended disappointingly last Sunday in Indianapolis.

The Colts quarterback knows plenty well what to expect from his old college coach, Jim Harbaugh, and a 49ers staff featuring several former Stanford coaches.

Luck and Harbaugh face off for the first time Sunday at Candlestick Park, each trying to get his 1-1 team back on track.

"It's going to be tough. They obviously got to the Super Bowl last year," Luck said. "I have a lot of respect for coach Harbaugh in my years at Stanford with him and coach (Vic) Fangio and the rest of the Stanford guys on their staff. They're a premier defense. It's going to be a great challenge but I think we're up for it. It'll be a fun week of work."

For Harbaugh, facing Luck might have a similar feel to coaching against his brother in the Super Bowl. Luck helped Harbaugh turn around Stanford's program and propel him into the NFL coaching ranks.

"There's not a lot of weaknesses that he has," Harbaugh said. "We're going to have to be very sound, very good. He's a top-notch quarterback in the NFL. Hopefully we'll be better for it as we play these top guys."

Emotions aside for players and coaches on both sides, here are five things to watch for Sunday:

Indianapolis tight end Coby Fleener, another former Stanford star, will be reunited with his college coaching staff, just like Luck.

Francois showed up for work Monday and went looking for Luck. He will offer any insight he can to help the offense, knowing Harbaugh loves to mix up things and pull out new wrinkles from that thick 49ers playbook.

"If nobody else asks me something, I said I know it's got to be Andrew Luck," Francois said. "I can give him some things, but I hope he don't ask for the signals because I'm on the front seven, I don't know nothing behind me. But I'm going to just help my offense the best I can, help my coaches to the knowledge of what I did, offense and defense-wise."

49ers tight end Vernon Davis will face cornerback brother Vontae for the first time — if big brother Vernon's tender hamstring allows it, that is.

KAEPERNICK BOUNCING BACK: A week after Colin Kaepernick threw for a career-high 412 yards and three touchdowns in a win against Green Bay, he produced his worst performance as a pro in a 29-3 loss at division rival Seattle. Kaepernick went 13 for 28 for 127 yards with three interceptions and was sacked three times.

"The biggest thing is we have to go out and execute," he said. "It's not really something they did, it's what we didn't do."

How he bounces back will be a key factor considering he had very little failure in a breakthrough 2012 and impressive postseason run.

"He probably played the best; most productive person we had on offense," Harbaugh said. "He did what he could."

TALE OF TWO HALVES: Indianapolis amassed 315 yards in the first half and 133 over the final two quarters in a 24-20 home loss to Miami, Luck's first defeat on his home field. The Colts led 17-14 at halftime after falling behind 14-3.

Coach Chuck Pagano is striving for improved consistency in all phases.

"We've got to play better," Pagano said. "We've got to play 60 minutes of consistent football on both sides of the ball and on special teams. We'll continue to look for ways to make sure that we can do that."

THE GORE FACTOR: Frank Gore wants to get on track, and now.

The franchise rushing leader has 30 carries for 60 yards in two games, with his longest gain for 8 yards. He had nine carries for 16 yards at Seattle.

An offensive line so dependable last year has struggled, while defenses have focused on stopping the run.

"We have to find a way, we have to get it done," Gore said.

Indy wants to quickly incorporate new RB Trent Richardson into the offense.

THE REPLACEMENTS: What a list of injuries and fill-ins for both teams.

The Colts lost left guard Donald Thomas and tight end Dwayne Allen for the year, while 49ers nose tackle Ian Williams was placed on season-ending injured reserve with a broken left ankle that required surgery. Veteran Glenn Dorsey takes over for him.

"Injuries are part of this game. We all understand that," Pagano said. "It'll be next man up."